There are cases where drivers would go through child device nodes and
operate on only the ones whose node name starts with a given prefix.
Provide a helper for these users. This will mainly be used in a
subsequent patch that implements a hardware component prober for I2C
busses.
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> Reviewed-by: Rob Herring (Arm) <robh@kernel.org> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>